Gear-tooth grinder



Aug. 3 1926.,

A. WILDER GEA R TOOTH GRINDER s, 1924 3 Sheets-Sheet 1 Filed Jan mvE/vron M Aug. 3,1926. 1594 A. L. WILDER 397 GEAR TOOTH GRINDER Filed Jan. 5. 1924 5 Sheets-Sheet 2 [NI/EN 70/? W/Mq A TTUHNEY IJIIII'IIII'IIIIIII INVENTOR Br v Y ATTflfl/VEY 3 Sheets-Sheet 3 Ill.

A. L. WILDER GEAR TOOTH GRINDER Fi led J an Aug. 3 1926.

Patented A ing 3, v

ARTHU'E L. 0Z5 WETLZZERSIFELD, GONNEGTEGUT, ASSIGIIQR IEO PRATT & WHIT-' 1 teaser creme,

GQEEZPMFY, fil HEW Ill. Y., A CORFPQBRATION OF NEW @EAR-TQQTH Application filedt'anuary 3, 19%. Serial No. GMJW.

This invention relates to a new form oi machine for grinding the tooth curves of gears.

An object of the invention is to provide-a machine and method which will permit grinding of tooth curves on gears of diilerent types and sizes which will be simple and e'ilicient in its operation.

More particularly it is an object of the present invention to provide a semi-automatic machine to carry out the method of grinding gears disclosed and claimed in the copending application of ldaag ti'l'lfl iQ filed November 30, 1923..

The above objects are. accomplished by means of mechanism permitting a blank to be rolled through a predetermined limited distance past one or more abrasive wheels, returned to its initial position without rolling action, and repeatedly rolled and returned. The rolling action is made substantially equal to or slightly greater than the circular pitch of the gear being ground.

Mechanism is also provided for slowly" changing the relative position oi the gear to the abrasive wheel or wheels duringits rolling movement so that the entire contour of each tooth is engaged and abraded by the action of the wheel or wheels.

Another object of the invention is to provide simple mechanism for accomplishing this rolling and returning movement of the blank, these means comprising a master gear on the work spindle corresponding in diameter and number of teeth to the gear being grouhd. Means also are provided to cause the master gear to be engaged and disengaged from a precision rack in timed relation to the rolling and returning motions of the geaiwblanlr and master gear. The rolling motion takes place with the master gear in mesh with the precision rack and with the gear blank in contact with the wheel or wheels. The return movement which takes place without rolling occurs when the master gear is out of mesh with the. rack and the gear blank entirely clear of the wheels.

in grinding gear-teeth heretofore it has been the practice. toroll a gear back and forth pasta wheel or'pair of wheels through the entire distance that its teeth contact with the wheels. Between each, or a succession of rolling-movements, the gear is. indexed, after which the rolling motion is repeated.

In the present invention, the gear is not rolled through a distance sufiicient to engage the abrasive wheel over the entire active con" tour of a tooth but the rolling motion is re stricted to a distance equal substantially to its circular pitch. Also, the rolling movement occurs in one direction only, the return movement taking place without rolling so that the gear blank isindexed to a new position each time it passes the abrasive wheels. While these rolling and return motions of the gear are taking place, which can occur ate high rate of speed, the blank is gradually advanoed laterally of the wheels so that the rolling and return motions occur in successively advanced positions. As soon as this advancing movement has reached a predetermined amount, determined by the contact line of the gear, a retrograde movement is given to the blank. The rolling and return movements are continued during this retrograde movement until the blank is rolled past the wheel in exactly the same path as at the beginning of the grinding operation.

It has also heretofore been the practice to edect a rolling motion of the blank being operated on and extend this rolling motion laterally suiiiciently to permit indexing.

This is usually done by rolling far enough to one side to completely disengage the wheel or wheels from the work so that the blank may be indexed by special mechanism while in that position. This added rolling motion however is sutiicient to materially increase the time of the grinding operation and so materially reduce the efficiency of the machine.

In the present invention the rolling motion is limited to a distance equal to the circular pitch of the gear being ground, which can take place at relatively high speed. Indexing of the gear is preferably accomplished by withdrawing the gear directl from the wheel or whee s at the end of one of a series of rolling movements and'returning it to its initial position without rolling; The gear is therefore moved bodil in a closed path of limited extent and, w ile in enga ement with the wheel or wheels is being in led to generate the tooth curves on the blanks.

in the present invention, no special indeib ing mechanism tor the gearhlank is requilted for the reason that the rolling move bill ltld

are

nail

ment in one direction and the return movement in the opposite direction without rolling or rotative motion indexes the blank through the space of one tooth each time. The mechanism may therefore be used for grinding gears having any numbers of teeth without the necessity of any special indexing mechanism.

A principal object of the n'lvention is therefore to provide simple mechanism to actuate the work blank in a manner to effeet the above cycle of operations With these and other objects in view, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawings.

In the accompanying drawings annexed hereto and forming a part of this specification, I have shown my invention embodied in a spur gear grinding machine but it will be understood that the invention can be otherwise embodied and that the drawings are not to be construed as defining or limiting the scope of the invention, the claims appended to the specification being relied upon for that purpose.

In the drawings:

Figure 1 is a plan view of the principal portions of a machinemade in accordance with the present invention.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1. p

Fig. 3 is a vertical sectional view of the principal actuating mechanism for the gear blank taken upon line 33 of Fig. 1.

Fig. 4 is a plan view of the mechanism for moving the master gear into and out of contact with the master rack, this view being taken substantially on line 44 of Fig. 3.

Fig. 5 is a plan View of the master gear showing its position relative to the master rack, this view being taken on line 55 of Fig. 3.

Fig. 6 is an enlarged view of a master gear in engagement with its rack showing the different positions of the master gear at different tions.

In the above mentioned drawings, I have shown but one embodiment of the invention which is now deemed referable, but it is to be understood that ciianges and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, m invention in its broadest aspect comprises the following principal parts: first, a base preferably having a column thereon; second, swinging arms supported by means of said column; third, a work spindle rotatably mounted at the free end of said swinging arms: fourth, a master gear on said work spindle; fifth, a rack but may periods of the cycle of operaneeine? fixed to said base and adapted to be engaged by the master gear on the spindle; sixth, a slidecarrying the actuating mechanism for the master gear and other parts on said spindle; seventh, means to slowly reciprocate said slide so that the relative position of the master gear and rack is continuously changed,- and eighth, one or more abrasive wheels adj ustably mounted on the base.

Referring more in detail to the figures of the drawings, I provide; a base 10 having secured thereto a column 11. This column, as shown, is provided near one end of the base and on one of its sides has mounted thereon attaching means for swinging arms 12 and 13. These arms 12 and 13 are in every way analogous to those disclosed in the copending application of Tanner and Knowles, Serial No. 621,307 filed Feb. 26, 1923, so that the method of attaching and supporting them does not require further explanation.

At the free end of these swinging arms is a suitable bearing for a vertical work supporting and rotating spindle 14. This spindle 14, at its upper end preferably is provided with a center 15 in alignment with an adjustable center 16 supported from the upper portion of the arm 13 so that a work arbor 17 may be supported between them. The work spindle 14 is provided also with a brake band 18 permitting a slight frictional engagement between itself and a portion of the spindle so that the work spindle 14 may be prevented from freely rotating be adjusted so that its driving members may rotate it positively and without lost motion or back lash.

On the work spindle 14 is a master gear 20, means being provided to readily remove itand replace it with other master gears of different, sizes and numbers of teeth. Below the master gear 20 is a ball bearing 21 or other annular member adapted to contact with a vertical plane surface 22 positioned adjacent a rack 23. For convenience, the rack and the plane vertical bearing surfaces are. mounted on a removable member 24 secured to the base 10 (see Fig. 5) permitting them to be readily dismounted and replaced with other racks23 of different pitch and adapted to coact with master gears 20 of different diameters.

'From the above, it will be seen that a work blank W suitably mounted onthe centers l5 and 16 provided on the work spindle -14 may be rolled by suitably moving the work spindle 14 while the master gear 20 is in contact with the rack 23. It is during a rolling motion of this type that the abrasive action occurs by contact' with the tooth flanks on the blank W with abrasive wheels 25, two of which are preferably used. As the abrasive wheels 25 may be mounted on wheel heads 25 substantially similar to those described in the above mentioned copending application, further description will be unnecessary. It will, be suificient to state that adjustments are provided for moving the wheel heads 25 so that the wheels 25 may be correctly positioned rela-, tive to the tooth flanks of the blanks, so that teeth of proper form may be generated. As shown in Fig. 1, the wheels 25 of suitable size are positioned to engage opposite sides of adjacent teeth on the blank "W and are placed in adjacent spaces of the work blank.

hese wheels 25 engage the teeth flanks of the blank W upon surfaces normal to the axis of the spindle upon which they are ro-- tated.

In order to cause the work spindle 14 to move in a direction to engage the master gear 20 with the rack 23 and so bring the work blank XV into contact with the abrasive wheels 25, the following mechanism is provided: A vertical cam shaft 26 is provided preferably rotated by a worm 27 and worm wheel 28 shown in Figs. 3 and 4. This cam shaft 26 as shown in the drawings is mounted on a horizontally movable slide 29. This shaft 26 near its upper portion is provided with two cams 30 and 31. The first cam 30 is in the form of a plate having a rim 32 of irregular contour extending from one side surface about a portion of its periphery. This cam portion 32 is adapted to contact with a roller 33 or other member mounted on a member in the form of a bell crank 34 so that with each rotation of the shaft 26 the bell crank 34 is oscillated back and forth. This bellcrank 34 also is mounted onithe slide 29- so that it moves therewith. The other cam 31 on this shaft 26 is in the form of a disc, the eriphery of which. is suitably shaped, and engages a roller- 35 mounted in alignment with the lower end of the work spindle 14. A link 36 pivotally attached to one arm of the bell crank34 surrounds a ball bearing 37 on the spindle 14 and serves tosupport the roller 35. In or der to maintain the roller 35 in contact with the disc cam 31 on the shaft 26, a spring ac tuated rod 40 is attached to the link 36 and normally forced in a direction to hold the link 36 toward the cam 31. The effect of this latter cam 31 is to cause the work spindle 14 to move in a direction parallel with the rack 23, this movement taking place while the master gear 20 is in engagement therewith so that the work spindle 14 is rotated, which causes a rolling motion of the master gear 20 along'the rack 23. The first mentioned cam 30 mounted on the shaft 26, which engages the roller 33-011 the bell crank 34 serves to oscillate this bell crank 34 and also reciprocate the link 36. The work spindle 14 by reason of this mechanism is moved in a direction normal to the rack23 so that the master gear 20 and rack 23 are alter- The resultant or combined movements induced by this above described mechanism is a short rolling movement of the master gear 20 and work blank W while the master gear 20 engages the rack 23 and while the spindle 14 is being moved in one direction. At that point of the cycle of operations, the first cam 30, by engaging the roller 33 on the bell crank 34, causes the master gear 20 to be disengaged from its rack 23 and the second cam 31' then returns the work blank W to its initial position by a movement lougitudinally relatively to the rack 23 without any rotation of the spindle 14. The first cam 30 then permits the work spindle 14 to movetoward the rack 23 so that the master gear 20 again engages it whereupon the cycle is repeated.

The length of rolling motion of the master gear 20 is governed entirely by the shape of the disc cam 31 and for that purpose this cam is made readily removable so that others having slightly different forms may be accomplished. The first cam 30 is made of such a shape that it moves the spindle 14 in a direction normal to the rolling movement sufficiently to completely disengage any master gear 20 from its rack 23. In carrying out the invention in its preferred form, the rolling motion of the master gear 20 is made substantially equal to or slightly greater than the circular pitch of the gear WV before being ground. As the wheels 25 are disposed directly above the rack 23 they engage and abrade the teeth, of the gear blank W while the master gear 20 engages the rack 23 and is being rolled therealong.

The work spindle 14 is held toward the rack'23 positively and therefore the position of the blank W relative to the abrasive wheels 25 is limited by the roller 21 on the spindle 14 engaging the vertical bearing surface 22 adjacent the rack 23. In order to resiliently hold the work spindle '14 and the mechanisms movable therewith toward the rack'23, the bell crank 34 is provided with a spring pressed rod 42 normally forced in one direction. The cam projection 32 does not extend entirely about the entire periphery of the plate 30. The ball 33 is therefore not continuously engaged by this cam. While the roller 33 is not engaged by the cam 32, the bell-crank 34 is held resiliently by the tension of rod 42 toward the guiding surface 22 and rack 23. The work spindle 14 is therefore held resiliently toward the wheels '25 by the arm 36 being forced in that direction by rod 42 through its-'Jattachment to the hell-crank 34.

The above described mechanism is sumgaged'by said master gear, cam means con trolling said blank and master gear to-successively roll them past said wheel in different indexed positions, and a slide carrying'said actuating means movable in the direction of the rolling motion.

8. A gear tooth grinding machine comprising in combination, a base, an abrasive wheel adjustably mounted thereon, a blank supporting and rotating spindle adapted to be moved in any direction while its axis is maintained always in parallel positions, means to effect a rolling movement of a blank on said spindle past said wheel, and means to move said spindle to engage and disengage said blank with said wheel, both of said means being mounted on and moving with a slide whereby a feeding movement or said blank may be effected.

9. A gear tooth rinding machine comprising 1n combination, abase, an abrasive wheel adjustably mounted thereon, a blank supporting and rotating spindleadapted tobe moved in any direction while its axis is maintained always in parallel positions,

. means to effect a rolling movement of a blank on said spindle past said wheel through a distance substantially equal to its circular pitch, and cam means to move said spindle to engage and disengage said blank with said wheel, both of said means being mounted on and moving with aslide whereby a feeding movement of said blank may be, effected in the direction of the rolling movement,

10. A gear tooth grinding machine comprising in combination, a base, an abrasive wheel adjustably mounted thereon, a blank supporting and rotating spindle adapted to be moved in any direction while its axis is maintained always in parallel positions, means to effect a rolling movement of a blank on said spindle past said wheel, means to move said spindle to engage and disengage said blank with said Wheel, both of said means being mounted on and moving with a slide whereby a feeding movement of said blank may be efl'ected, and crank and connecting rod means to move said slide in the direction of the rolling movement.

In testimony whereof, I hereto aflix my 50 signature.

ARTHUR L. WILDER 

